Provided by: db6.0-util_6.0.19-3ubuntu1_amd64 bug

NAME

     db6.0_codegen — generate application code for Berkeley DB

SYNOPSIS

     db6.0_codegen [-Vv] [-a api] [-i file] [-o prefix]

DESCRIPTION

     The db6.0_codegen utility generates application code to create and configure Berkeley DB
     database environments and databases based on a simple description language and writes it to
     one or more output files.  The generated code may need modification, in the case of
     complicated applications, but will usually significantly reduce the time required to create
     Berkeley DB applications.

     The options are as follows:

     -a api
          Generate code for the specified API (currently, only “c” is accepted).

     -i file
          Specify an input file; by default, standard input is used.

     -o prefix
          Specify an output file prefix; by default, “application” is used.

     -V   Write the library version number to standard output and exit.

     -v   Run in verbose mode.

     The db6.0_codegen utility exits 0 on success, and >0 if an error occurs.

C Language Specific Information

     By default, when the db6.0_codegen utility generates C-language code, the output file is
     named “application.c”.  The output filename can be specified with the -o option.

     At the beginning of the output file is a list of public database environment (DB_ENV)
     handles and database (DB) handles, as specified by the description language.  The database
     environment handle variables are named “XXX_dbenv”, where “XXX” is the name of the
     environment in the input specification.  For databases associated with a database
     environment, the database handle variables are named “XXX_YYY”, where “XXX” is the name of
     the environment, and “YYY” is the name of the database.  For standalone databases, the
     database handle variables are named “XXX”, where “XXX” is the name of the database.

     There are two public functions in the output file: bdb_startup() and bdb_shutdown().  The
     bdb_startup() function should be called to create and configure the database environments
     and databases, and the bdb_shutdown() function should be called to gracefully shut down the
     environments and databases.

Specification Language

     The db6.0_codegen uses a simple description language:

     ·   Lines in the input consist of white-space separated tokens.
     ·   Tokens are case-insensitive.
     ·   Empty lines and lines where the first non-space character is a hash mark (“#”) are
         ignored.  In addition, hash marks may appear in lines, in which case the content of the
         line from the hash mark to the end of the line is ignored.

     There are two top-level objects: “environment” and “database”, which correspond to database
     environments and databases, respectively.  These top-level objects can be associated with
     keywords to describe their configuration and relationships.

     For example, the following input would create two standalone databases:

           database data_one {
               type btree
           }
           database data_two {
               type btree
           }

     In this case, there would be no DB_ENV handle, and the public DB handles would be:

           DB      *data_one;
           DB      *data_two;

     For example, the following input would create a database environment which contains three
     databases:

           environment myenv {
               database data_one {
                   type btree
               }
               database data_two {
                   type btree
               }
               database data_three {
                   type btree
               }
           }

     In this case, the public DB_ENV and DB handles would be:

           DB_ENV  *myenv_dbenv;
           DB      *myenv_data_one;
           DB      *myenv_data_two;
           DB      *myenv_data_three;

     A variety of keywords can be specified for the databases and the environments.  For example,
     the cache size can be specified for the database environment, and the page size can be
     specified for the database, as well as for secondary relationships:

           environment myenv {
               cachesize 2 0 10
               database data_one {
                   type btree
                   pagesize 1024
               }
               database data_two {
                   primary data_one
                   secondary_offset 10 15
                   type btree
                   pagesize 32768
               }
               database data_three {
                   type btree
                   pagesize 512
               }
           }

   Environment Keywords
     environment       Start a database environment block.

                       There must be three tokens on the line: the keyword, the name of the
                       environment and an opening brace (“{”).

     home              Specify the database environment home directory.

                       There must be two tokens on the line: the keyword and the home directory.

     cachesize         Specify the database environment cache size.

                       There must be two tokens on the line: the keyword, the gigabytes of cache,
                       the bytes of cache, and the number of caches (the number of underlying
                       physical areas into which the cache is logically divided).

     private           Specify the database environment is private.

                       There must be one token on the line: the keyword by itself.

     }                 End the database environment block.

                       There must be one token on the line: the keyword by itself.

   Database Keywords
     database          Start a database block.

                       There must be three tokens on the line: the keyword, the name of the
                       database and an opening brace (“{”).

     custom            Specify a custom key-comparison routine.  This is used when the Btree
                       database requires a specific sort that db6.0_codegen cannot generate.  A
                       stub key comparison routine will be created and configured for the
                       database which should be modified as necessary.  See the “key_type”
                       keyword for more information.

                       There must be one token on the line: the keyword by itself.

     dupsort           Configure the database to support sorted duplicates.

                       There must be one token on the line: the keyword by itself.

     extentsize        Configure the size of the Queue database extent files.

                       There must be two tokens on the line: the keyword and the extent file
                       size, as a number of pages.

     key_type          Configure a integral type key-comparison routine.  This is used when the
                       Btree database key is an integral type (such as “unsigned int” or
                       “u_int32_t”).  Any C-language integral type may be specified.  See the
                       “custom” keyword for more information.  A Btree comparison routine based
                       on the type of the key will be created and configured.

                       There must be two tokens on the line: the keyword and the type.

     pagesize          Configure the database page size.

                       There must be two tokens on the line: the keyword and the page size in
                       bytes.

     primary           Configure the database as a secondary index.  A stub secondary callback
                       routine will be created and configured for the database, which should be
                       modified as necessary.  See the “secondary_offset” keyword for more
                       information.

                       There must be two tokens on the line: the keyword and the name of the
                       primary database for which this database is a secondary.

     recnum            Configure the Btree database to support record number access.

                       There must be one token on the line: the keyword by itself.

     re_len            Configure the record length for a Queue database or a fixed-length Recno
                       database.

                       There must be two tokens on the line: the keyword and the length of a
                       record, in bytes.

     secondary_offset  Configure a secondary callback routine based on a byte string found in the
                       primary database's data item.

                       There must be three tokens on the line: the keyword, the byte offset from
                       the beginning of the primary data item where the secondary key occurs, and
                       the length of the secondary key in bytes.

     transaction       Configure the database (and, by extension, the database environment), to
                       be transactional.

                       There must be one token on the line: the keyword by itself.

     type              Configure the database type.

                       There must be two tokens on the line: the keyword and the type, where the
                       type is one of “btree”, “hash”, “queue” or “recno”.

     }                 End the database environment block.

                       There must be one token on the line: the keyword by itself.

AUTHORS

     Thorsten Glaser <tg@debian.org> wrote this manual page for the Debian project (but may be
     used by others) after the original HTML format documentation Copyright © 1996,2008 Oracle.
     All rights reserved.